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use std::env;
use std::fs::File;
use std::io;
use std::io::BufRead;
use std::collections::HashMap;
fn main() -> io::Result<()> {
for filename in env::args().skip(1) {
let mut f = File::open(&filename)?;
let mut reader = io::BufReader::new(f);
let counts = count_words(&mut reader)?;
print(&counts, 10)
}
Ok(())
}
fn count_words(reader: &mut io::BufReader<File>) -> io::Result<WordCounts> {
let mut counts = WordCounts::new();
for line in reader.lines() {
let line = line?;
add_counts(&mut counts, &count_words_in_line(&line));
}
Ok(counts)
}
fn count_words_in_line(line: &str) -> WordCounts {
let mut counts = WordCounts::new();
let mut word = String::new();
for c in line.chars() {
if c.is_alphabetic() {
word.push(c);
} else {
if !word.is_empty() {
count(&mut counts, word.clone());
word.clear();
}
}
}
if !word.is_empty() {
count(&mut counts, word.clone());
}
counts
}
type WordCounts = HashMap<String, u32>;
fn count(counts: &mut WordCounts, word: String) {
add(counts, word, 1);
}
fn add_counts(counts: &mut WordCounts, other: &WordCounts) {
for (word, count) in other.iter() {
add(counts, word.to_string(), *count);
}
}
fn add(counts: &mut WordCounts, word: String, count: u32) {
let counter = counts.entry(word).or_insert(0);
*counter += count;
}
fn print(counts: &WordCounts, max: usize) {
let mut top = Vec::new();
for (word, count) in counts.iter() {
top.push((count, word));
if top.len() > max {
top.sort();
top.reverse();
top.truncate(max);
}
}
for (count, word) in top.iter() {
println!("{} {}", count, word);
}
}
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